Sorry for the late response, I’ve been giving these a try lately and just haven’t been able to reproduce what you have been seeing. I think we’d need support eyes on your system to really get a good idea as to what’s going on.
I will mention that during version mismatch, syncing does not take place as the connection in this instance basically only allows the master to disable the backup. However as of 8.1.19 with change 2393, a lot of the duplicate alarm and tag status issues should function a bit better.